Substrate measuring device and a method of using the same

ABSTRACT

Embodiments of the present disclosure provide methods for processing a substrate using a measuring device in a lithography projection apparatus that provides multiple light sources having different wavelengths. In some embodiments, a lithography projection apparatus includes a substrate measuring system disposed proximate to a substrate stage, the substrate measuring system further including an emitter including multiple light sources configured to provide multiple beams of light, each of at least some of the multiple beams of light having a different wavelength, at least one optical fiber, wherein each of respective zones of the at least one optical fiber is configured to pass a respective one of the multiple beams of light, and a receiver positioned to collected light emitted from the emitter and reflected off of a substrate disposed on the substrate stage.

RELATED APPLICATION

This application is a Divisional Application, under U.S.C. § 120, ofU.S. patent application Ser. No. 16/049,678 filed Jul. 30, 2018.

BACKGROUND

The semiconductor integrated circuit (IC) industry has experiencedexponential growth. Technological advances in IC materials and designhave produced generations of ICs where each generation has smaller andmore complex circuits than the previous generation. In the course of ICevolution, functional density (e.g., the number of interconnecteddevices per chip area) has generally increased while geometry size(e.g., the smallest component (or line) that can be created using afabrication process) has decreased. This scaling down process generallyprovides benefits by increasing production efficiency and loweringassociated costs.

Photolithography has been used to form components on a chip. As thedimensions of the integrated circuit components are reduced, thelithography process is required to transfer even smaller features onto asubstrate precisely, accurately, and without damage. The desire of thehigh resolution lithography process has led to challenges that may nothave been presented by previous generations at larger geometries.

BRIEF DESCRIPTION OF THE DRAWINGS

Aspects of the present disclosure are best understood from the followingdetailed description when read with the accompanying figures. It isnoted that, in accordance with the standard practice in the industry,various features are not drawn to scale. In fact, the dimensions of thevarious features may be arbitrarily increased or reduced for clarity ofdiscussion.

FIG. 1 depicts a schematic view of an example lithography projectionapparatus including a substrate measuring device in accordance with someembodiments.

FIG. 2 depicts a schematic view of another example of a lithographyprojection apparatus including a substrate measuring device inaccordance with some embodiments.

FIGS. 3A-3D depict beams of light from an emitter of a substratemeasuring device incident on different locations of a substrate withdifferent surface topographies in accordance with some embodiments.

FIG. 4 depicts an optical fiber in accordance with some embodiments.

FIG. 5 depicts a plurality of optical fibers in accordance with someembodiments.

FIG. 6 depicts beams of light incident on different locations of asubstrate with different surface topographies in accordance with someembodiments.

FIGS. 7A-7D depict emitters with different fibers and configurations ofshields formed therein in accordance with some embodiments.

FIG. 8 depicts an emitter with a shield and different fibers formedtherein in accordance with some embodiments.

FIG. 9 depicts a flow chart of performing a substrate alignment processin accordance with some embodiments.

DETAILED DESCRIPTION

The following disclosure provides many different embodiments, orexamples, for implementing different features of the provided subjectmatter. Specific examples of components and arrangements are describedbelow to simplify the present disclosure. These are, of course, merelyexamples and are not intended to be limiting. For example, the formationof a first feature over or on a second feature in the description thatfollows may include embodiments in which the first and second featuresare formed in direct contact, and may also include embodiments in whichadditional features may be formed between the first and second features,such that the first and second features may not be in direct contact. Inaddition, the present disclosure may repeat reference numerals and/orletters in the various examples. This repetition is for the purpose ofsimplicity and clarity and does not in itself dictate a relationshipbetween the various embodiments and/or configurations discussed.

Further, spatially relative terms, such as “beneath,” “below,” “lower,”“above,” “upper” and the like, may be used herein for ease ofdescription to describe one element or feature's relationship to anotherelement(s) or feature(s) as illustrated in the figures. The spatiallyrelative terms are intended to encompass different orientations of thedevice in use or operation in addition to the orientation depicted inthe figures. The apparatus may be otherwise oriented (rotated 90 degreesor at other orientations) and the spatially relative descriptors usedherein may likewise be interpreted accordingly.

Generally, the present disclosure provides example embodiments relatingto a substrate measuring device used in a lithography projectionapparatus. The substrate measuring device includes an emitter thatprovides multiple light sources having different wavelengths. Thesubstrate measuring device further includes a receiver that detectsresponses to the light having different wavelengths reflected from asubstrate. The light (having different wavelengths) reflected from thesubstrate is used to determine variations of height and/or a profile ofa substrate surface. Thus, a better prediction of the substrate profilecan be obtained so as to determine a vertical position of the substraterelative to a focal plane for the subsequent lithography exposureprocess with improved resolution. The beams of light from the multiplelight sources are guided by an optical fiber or a plurality of opticalfibers formed in the emitter. The beams of light guided from the opticalfiber(s) are then emitted to desired locations of the substrate so thereceiver can detect reflected light, which can be used to determine asubstrate profile. The determined substrate profile can assist alignmentof the substrate for the subsequent lithography exposure process. Theoptical fiber may have multiple zones fabricated from the same ordifferent materials to guide each individual light source with a certainwavelength. Additionally or alternatively, the plurality of opticalfibers in the emitter may have different optical fibers guidingdifferent beams of light of different wavelengths.

FIG. 1 depicts a lithography projection apparatus 100 that may be usedto provide beam energy to a photoresist material disposed on a substrateduring a lithography exposure process. In some embodiments, thelithography projection apparatus 100 comprises a radiation source 101disposed above a photomask reticle 102. The radiation source 101 mayprovide a beam of radiation 110 with a desired wavelength. In someexamples, the radiation source 101 provides and emits the beam ofradiation 110 at a wavelength in a range from about 10 nm to about 2000nm, such as about 13.5 nm, 135 nm, 157 nm, 193 nm, 248 nm, or 365 nm.The beam of radiation 110 passes through the photomask reticle 102 to anoptical focusing module 104. The optical focusing module 104 transformsthe beam of radiation 110 emitted by the radiation source 101 using atleast one lens (not shown) in the optical focusing module 104 into aline, spot, or other suitable beam configuration to be further directedat a photoresist material disposed on a semiconductor substrate 106disposed on a stage 112. The lens in the optical focusing module 104includes any suitable lens, or series of lenses, capable of focusingradiation into a line or spot. In some embodiments, the optical focusingmodule 104 includes a cylindrical lens. In some embodiments, the opticalfocusing module 104 includes one or more concave lenses, convex lenses,plane mirrors, concave mirrors, convex mirrors, refractive lenses,diffractive lenses, Fresnel lenses, gradient index lenses, or the like.

The beam of radiation 110 is selectively applied to certain areas of thesubstrate 106 to provide radiation energy to discrete predeterminedregions of the substrate 106. The stage 112 is configured to support thesubstrate 106, and a translation mechanism 124 is configured to controlvertical and lateral movement of the stage 112.

A substrate measuring device 150 is disposed proximate to the substrate106. The substrate measuring device 150 includes an emitter 116 and areceiver 118. The emitter 116 is disposed above the stage 112. Theemitter 116 provides beams of light 120 (e.g., a signal) with differentwavelengths emitted to the surface of the substrate 106. The beams oflight 120 are then reflected from the substrate 106 and are collected bythe receiver 118. The receiver 118 generates data or information basedon the light 120 collected by the receiver 118. For example, the data orinformation can be digital data corresponding to intensity and/orlocation of the light 120 that is collected by the receiver 118. Asexamples, the receiver 118 can be an image sensor (e.g., a CMOS imagesensor), a charged coupled device (CCD), or the like. The receiver 118may include one or more light filters for distinguishing betweendifferent wavelengths of light. The data or information generated by thereceiver 118 based on the collected light 120 is transmitted to acontroller 108 and to a data computing system 190. The data computingsystem 190 analyzes the data or information to obtain informationregarding the surface topography and profile of the semiconductorsubstrate 106 positioned on the stage 112 and to determine an upper mostsurface of the substrate 106.

The substrate measuring device 150 (with the emitter 116 that provides alight source with different wavelengths and a corresponding receiver 118capable of collecting light of different wavelengths) may be used todetermine various properties or characteristics of, for example, filmson the semiconductor substrate 106. For example, data or informationgenerated by the receiver 118 can be analyzed to determine differentresponses by the films to having light with different wavelengthsincident thereon. Accordingly, the substrate measuring device 150 isconfigured to distinguish between responses to light at differentwavelengths. For example, the emitter 116 can serially emit light with asingle wavelength or narrow wavelength spectrum (with each serialemission being at a different wavelength), and hence, the receiver 118can serially collect light at different wavelengths for analyzing theresponses of the films to the light at those wavelengths. In otherexamples, the emitter 116 can emit light with multiple wavelengthssimultaneously or in parallel, and the receiver 118 can have aconfiguration of filters to attenuate or exclude light outside of awavelength band of the respective filter so the receiver 118 can isolatea response to a given wavelength. With data or information generated bythe receiver 118 corresponding to a given wavelength or narrowwavelength spectrum, the data or information may be used to detectdifferent film properties or characteristics, such as local thickness,stress, refractive index and extinction coefficient (n & k), surfaceroughness, variation of height, surface profile, surface topography, orresistivity on the substrate 106 prior to performing a lithographyexposure process.

The data generated by the data computing system 190 in response to datagenerated by the substrate measuring device 150 may also help toidentify the coordinate, alignment, or orientation of the substrate 106so as to enhance the alignment of the substrate 106 for the followinglithography exposure process. The emitter 116 and the receiver 118 maybe coupled to a controller 108, so as to control movement of the stage112 and data transfer from the receiver 118.

The controller 108 may be a high speed computer that communicates withthe data computing system 190. The data points generated by thesubstrate measuring device 150 are transmitted to the controller 108 andthen to the data computing system 190 to determine a profile/structureof substrate 106. With the profile/structure of the substrate 106determined, a proper location or leveling position for the substrate 106may be determined to perform alignment for the lithography process. Forexample, with the profile/structure of the substrate 106, the controller108 can determine at what location (e.g., including vertically) tooptimally position the substrate 106 within or near a focal plane of thelithography process. After the alignment process, the substrate 106 isthen ready for a lithography exposure process performed in thelithography projection apparatus 100.

In some embodiments, the translation mechanism 124 may be configured totranslate the stage 112 vertically and/or laterally. The translationmechanism 124 may be configured to move the stage 112 in differentdirections. In some embodiments, the translation mechanism 124 iscoupled to the stage 112 and is adapted to move the stage 112 relativeto the emitter 116 and/or the receiver 118 and relative to the opticalfocusing module 104. In another embodiment, the translation mechanism124 may also control the movement of the radiation source 101 and/or theoptical focusing module 104 to cause a focal plane of the beam ofradiation 110 to move relative to the substrate 106 that is disposed onthe stage 112. Any suitable translation mechanism 124 may be used, suchas a conveyor system, rack and pinion system, an x/y actuator, a robot,or other suitable mechanical or electro-mechanical mechanism.Additionally and/or alternatively, the stage 112 may be configured to bestationary, while a plurality of galvanometric heads (not shown) may bedisposed around the substrate edge to direct radiation from the beam ofradiation 110 to the substrate 106.

The translation mechanism 124 may be coupled to the controller 108 tocontrol the speed at which the stage 112 moves relative to the emitter116, the receiver 118, the radiation source 101, and/or the opticalfocusing module 104. The controller 108 may receive data from thereceiver 118 or from the data computing system 190 to generate anoptimized focal plane that is used to control the lithography projectionapparatus 100.

The substrate measuring device 150 is used to determine the height,slope, surface topography, profile, upper most surface, and/or generalstructure of the substrate 106. The stage 112 is raised or lowered basedon the determined profile/structure of the substrate 106 so as to ensurethat the uppermost surface of the substrate 106 is located in or closeto the focal plane defined from the optical focusing module 104. Thesubstrate measuring device 150 assists determining a location where thesubstrate 106 with different profiles/structures of the material layersformed on the substrate 106 may be located during the lithographyexposure process, thus promoting the accuracy and resolution for thefollowing lithography exposure process. One factor that can influencethe imaging quality of the lithography projection apparatus 100 is theaccuracy with which the image from the photomask reticle 102 is focusedon the substrate 106. However, the scope for adjusting the position ofthe focal plane of the optical focusing module 104 can be limited, andthe depth of focus of the lithography projection apparatus 100 may alsobe small, thus rendering a relatively tight process window for theexposure area of the substrate 106. The presence of the structures fromthe previous process steps may also affect the height of the substrateand the flatness of the substrate surface. Thus, precise measurement ordetermination of the focal plane relative to the upper most surface ofthe substrate 106 can affect the resolution and the accuracy of theimage transfer from the photomask reticle 102 to the photoresistmaterial disposed on the substrate in the lithography exposure process.

FIG. 2 depicts another example of a lithography projection apparatus200, similar to the lithography projection apparatus 100 in FIG. 1, butwith a polarizer 222 or a beam splitter disposed adjacent to the emitter116. The polarizer 222 permits a portion of the beams of light 120 atcertain wavelengths to be passed therethrough to the substrate 106. Whena certain wavelength is desired for detection, the polarizer 222 may beutilized. The polarizer 222 is rotatable to adjust the incident anglefrom the beams of light 120 to allow a certain portion of the beams oflight 120 with a certain wavelength or polarity to pass therethrough.Based on different types of the polarizer 222 selected, differentalgorithms or computational methods stored in the controller 108 and/orthe data computing system 190 may be used as needed.

FIGS. 3A-3D depict a substrate profile under the measure of thesubstrate measuring device. The substrate measuring device includes anemitter 116 a, 116 b, 116 c, 116 d that provides different wavelengths.In some embodiments, the emitter 116 a, 116 b, 116 c, 116 d providesmultiple light sources. The multiple light sources provide beams oflight of different wavelengths, and the materials on the substrate havedifferent transmittances and reflectivities in response to the differentwavelengths. Thus, by utilizing the emitters 116 a, 116 b, 116 c, 116 dcomprising multiple light sources with different wavelengths, a widerrange of wavelength spectrum may be obtained. The wider wavelengthspectrum can permit better prediction and determination of a profile ofthe surface on the substrate 106 and the location of the focal plane302. When the multiple light sources are utilized, each light source mayscan across the substrate to determine the profile of the substrate. Thelight source may scan across the substrate by moving the stage 112 wherethe substrate is positioned or by actuating the emitter 116 a, 116 b,116 c, 116 d to scan across the substrate. Each emitter 116 a, 116 b,116 c, 116 d may scan across the substrate with the same or differentdata collecting points on the substrate.

For example, the emitter 116 a, as depicted in FIG. 3A, provides a beamof light at a first wavelength. Material on the substrate 106 may have agiven reflectivity and transmissivity in response to the firstwavelength. The beam of light at the first wavelength can penetratethrough a photoresist layer 305 and reflect back from a top surface 306(e.g., an upper most) of a material layer 304 (e.g., a dielectricmaterial or a metal material) disposed on the substrate 106. Thephotoresist layer 305 will be later exposed in the following lithographyexposure process. Thus, the height, location, and/or the position of anupper most surface of the material layer 304 on the substrate 106 may bepredicted, calculated, and/or obtained.

The emitter 116 b, as depicted in FIG. 3B, provides a beam of light at asecond wavelength different from the first wavelength. Based ondifferent materials on the substrate 106, the beam of light maypenetrate to a sidewall 308 (or a curved bottom corner) of thephotoresist layer 305. Thus, the beam of light may be reflected from thesidewall 308 of the material layer 304 surrounded with the photoresistlayer 305. The emitter 116 c, as depicted in FIG. 3C, provides a beam oflight at a third wavelength that may be able to reach to a bottomsurface 310 of the indentation 309 and that may be reflected off of thebottom surface 310. The emitter 116 d, depicted in FIG. 3D, provides abeam of light at a fourth wavelength. The photoresist layer 305 may havea relatively low transmissivity to the beam of light at the fourthwavelength such that the beam of light may be reflected once the beam oflight is incident on the photoresist layer 305.

In each of FIGS. 3A-3D, the receiver 118 collects beams of lightreflected from material on the substrate 106 and generates data orinformation based on the collected beams of light. The data orinformation generated by the receiver 118 is transmitted to thecontroller 108 and/or the data computing system 190. The data computingsystem 190 determines a profile/structure of the substrate 106. Thus, bycollecting the data points based on light having different wavelengths,a more precise and accurate prediction of the profile, surfacetopography, variations of the heights, contour, and/or structures on thesubstrate 106 may be obtained, which may be used to define a moreaccurate vertical position of the substrate 106 relative to the focalplane 302. Furthermore a vertical position and/or horizontal position ofthe substrate may also be better determined and subsequently aligned.

FIG. 4 depicts an embodiment of an optical fiber 402 that may beimplemented in the emitter 116. The optical fiber 402 includes multiplezones 404, each of which includes strands of optical fibers. Thedifferent zones 404 allow different wavelength light 410 a, 410 b, 410c, 410 d to pass therethrough. The optical fiber 402 in FIG. 4 includesfour zones 404 a, 404 b, 404 c, 404 d. In other examples, the opticalfiber 402 may include more or less than four zones. Each zone 404 a, 404b, 404 c, 404 d is capable of transmitting a different respectivewavelength light 410 a, 410 b, 410 c, 410 d. A light source of theemitter 116 can provide different wavelength light 410 a, 410 b, 410 c,410 d to different zones of the optical fiber 402 for transmissiontherethrough. In some examples, the light source of the emitter 116 is abroad spectrum light source having filters to filter differentwavelength light 410 a, 410 b, 410 c, 410 d. In other examples, thelight source of the emitter 116 includes a plurality of light sources,which each generating light at a different wavelength.

In some examples, light transmitted through the zones 404 a, 404 b, 404c, 404 d is in a wavelength spectrum from about 100 nm to about 2000 nm.In some examples, the optical fiber 402 may have (i) a first zone 404 afor transmitting a first wavelength light 410 a, e.g., at a UV lightrange having a wavelength around 248 nm, (ii) a second zone 404 b fortransmitting a second wavelength light 410 b, e.g., at a UV light rangehaving a wavelength around 193 nm, and (iii) a third zone 404 c fortransmitting a third wavelength light 410 c, e.g., at a UV light rangehaving a wavelength around 365 nm. The optical fiber 402 may furthercomprise a fourth zone 404 d for transmitting a fourth wavelength light410 d, e.g., at a visible light range having a wavelength of about 632nm. It is believed that the light sources with shorter wavelength (suchas UV light) can expose structures on the substrate with smallerdimensions at better resolution.

In some examples, the optical fiber 402 is micro-structured from one,two, or more materials so as to be divided into different zones 404 a,404 b, 404 c, 404 d. The four different zones 404 a, 404 b, 404 c, 404 dmay be fabricated from the same or different materials. The opticalfiber 402 may be fabricated by silica, glasses, quartz, amorphouscarbon, polymer materials, or other suitable materials. It is noted thatdifferent materials used in the optical fiber 402 may influence thebandgap of the beam of light transmitted therethrough. Thus, byselection of the materials of optical fiber 402 as well as the sourcesof the different wavelength light 410 a, 410 b, 410 c, 410 d, multiplelight sources with a desired range of wavelengths and intensities can beobtained and guided to desired locations of the substrate 106. In someexamples, the optical fiber 402 is fabricated from quartz or opticallytransmittable plastic material.

The materials of the substrate 106 through or on which the differentwavelength light 410 a, 410 b, 410 c, 410 d passes or is incident,respectively, may have different transmissivity and/or reflectivity inresponse to the different wavelength light 410 a, 410 b, 410 c, 410 d.As each incoming substrate may have its specific type of photoresistmaterial disposed thereon for device manufacturing requirements, theoptical fiber 402 that provides different wavelength light 410 a, 410 b,410 c, 410 d from multiple light sources may provide a wide spectrum ofwavelengths to accommodate different photoresist materials (e.g., withvarious transmissivity and reflectivity) disposed on the substrate. As aresult, a more accurate profile or contour of the surface profile on thesubstrate under the photoresist material may be mapped out andpredicted.

FIG. 5 depicts a plurality of optical fibers 502 that may be implementedin the emitter 116. The plurality of optical fibers 502, as illustrated,includes optical fibers 504, 506, 508. Each optical fiber 504, 506, 508is adapted to transmit light having a wavelength(s) different fromothers of the optical fibers 504, 506, 508. The optical fibers 504, 506,508 may be bundled together to allow light to pass through eachcorresponding optical fiber 504, 506, 508 so as to guide the beams oflight to a desired location on the substrate. Similar to the multiplewavelength light 410 a, 410 b, 410 c, 410 d depicted above, multiplewavelength light 510 a, 510 b, 510 c also provide beams of light atdifferent wavelengths to pass through the respective optical fibers 504,506, 508. As a result, beams of light having different wavelengths aretransmitted to a substrate. The different wavelength light can reachdifferent depths of the structures on the substrate (e.g., above thephotoresist material surface, above the structure on a substrate, or ona bottom of a structure on a substrate, and the like), which can providea better prediction of the profile of the structure on the substrate.Thus, utilizing these data points as collected, a vertical and lateralrelationship of the substrate to the focal plane may be more preciselydetermined for the following lithography exposure process with higherresolution.

In some examples, each individual optical fiber 504, 506, 508 in theplurality of optical fibers 502 may be fabricated from certain types ofmaterials so as to maximize the efficiency and intensity of the lightguided therethrough. In some examples, the optical fibers 504, 506, 508in the plurality of optical fibers 502 may be fabricated from the sametype of the materials to provide consistent and reliable light sourcestability.

FIG. 6 depicts beams of light emitted to different locations of asubstrate with different surface topographies in accordance with someembodiments. A first beam of light 602 having a first wavelength reachesto an uppermost surface 610 of the material layer 304 disposed on thesubstrate 106. A second beam of light 604 having a second wavelengthreaches to a lower surface 612 of the material layer 304 disposed on thesubstrate 106. A third beam of light 606 having a third wavelength emitsto the photoresist layer 305 disposed on the material layer 304 so as topredict a thickness of the photoresist layer 305. It is noted that thethird beam of light 606 may be stopped at any depth in the photoresistlayer 305 for thickness or profile prediction based on its wavelength. Afourth beam of light 608 having a fourth wavelength reflects from a topsurface 612 of the photoresist layer 305 so that the leveling and heightof the photoresist layer 305 may be detected and determined. Thus, bycollecting and analyzing the information from the reflected beams oflight by the receiver 118, the surface profile, as well as thethickness, leveling, and height of the photoresist layer 305, across thesubstrate 106 may be mapped, calculated, and/or determined so as tobetter position the substrate relative to a focal plane.

It is noted that, although four beams of light are shown in FIG. 6, anynumber of beams of light having different wavelengths may be used toassist measuring and mapping the substrate profile for better alignmentof the substrate.

FIGS. 7A-7D depict different examples of emitters 702, 704, 706, 708 inaccordance with some embodiments. The emitters 702, 704, 706, 708include an outer cast 712, 714, 716, 718 enclosing a plurality ofoptical fibers 722, 724, 726, 728, respectively. Similar to theconfigurations depicted in FIGS. 4 and 5, the plurality of opticalfibers 722, 724, 726, 728 enclosed by the outer cast 712, 714, 716, 718may include multiple materials or a single material to provide awaveguide to guide the light having different wavelengths to the desiredlocations on the substrate. The outer cast 712, 714, 716, 718 may be inany shape or configuration, such as shown in FIGS. 7A-7D.

FIG. 7B depicts another example of the emitter 704 that has a shield732. The shield 732 shields light paths of the light travelling througha portion of the plurality of optical fibers 724. The shield 732 mayshield the light paths passing through a portion of the optical fibers724 in the outer cast 714, which can block some beams of light atcertain wavelengths from reaching the substrate 106. In some embodimentswherein certain locations of the substrate may need to be inspected ordetected, the shield 732 can be utilized to block the light paths from aportion of the optical fibers 724, which can allow desired beams oflight at certain wavelengths to be emitted to the substrate surface. Bydoing so, beams of light at certain wavelengths may be selected based ondifferent materials or device properties of the incoming substrate sothat process parameters may be better determined.

In some embodiments, the shield 732 may be a metal plate that has highreflectivity and low transmittance to efficiently block the light pathsof the beams of light transmitted through the optical fibers 724. Theshield 732 may be located in any suitable location in the emitter 704.In some embodiments, the shield 732 has a rectangular shape covering oneside, as shown in FIG. 7B, or multiple sides, as shown in FIG. 7C, inhorizontal and/or vertical directions where the optical fibers 724 arelocated. In some embodiments, the shield 736 may serve as a framecovering an outer perimeter of the optical fibers 728 having a centeropening exposing the optical fibers 728 located in the center of theemitter 708, as shown in FIG. 7D.

FIG. 8 depicts another embodiment wherein the emitter 800 is in acylindrical configuration. A shield 802 may be in a ring shape thatcovers an outer portion of the optical fibers 804, and that exposes acenter portion of the optical fibers 804 by a center opening through theshield 802. It is noted that the shield 802, 732, 736 may be in anyconfiguration to accommodate the shapes, configurations, and designs ofthe emitters utilized to perform the substrate mapping process.

FIG. 9 depicts an exemplary flow diagram of a substrate alignmentprocess 900 that utilizes the substrate measuring devices describedabove. The substrate alignment process 900 begins at operation 902 byproviding a substrate, such as the substrate 106, on a stage in alithography projection apparatus, such as the lithography projectionapparatus 100 depicted in FIG. 1. The lithography projection apparatus100 includes the substrate measuring device 150 (with the emitter 116and receiver 118) disposed therein to be implemented for predicting andmapping the profile and structures on the substrate. It is noted thatthe lithography projection apparatus 100 may include more than one stageto separately perform the substrate alignment process and thelithography exposure process on the substrate.

As discussed above, the substrate includes a photoresist materialdisposed on a material layer. The material layer may include structures,multiple layers, a stack of film layers, or other suitable materials formanufacturing a device structure. The photoresist material is disposedon the material layer for exposure after the alignment process.

At operation 904, after the substrate is placed on the stage disposed inthe lithography projection apparatus, multiple wavelength lights areprovided from the emitters of the substrate measuring device. Asdiscussed above, the emitters provide multiple wavelength light sourcesthat emit beams of light having different wavelengths to the substrate.The beams of light with different wavelengths may be emitted to aplurality of locations of the substrate. Different materials on thesubstrate can have various transmissivities and reflectivities to thelight with different wavelengths, and hence, can have differentresponses to the light with different wavelengths when the light isincident on and/or passes through the materials. In some embodiment, thesubstrate often includes physical references (e.g., or called alignmentmarks) located at least two opposite sides of the substrate surface toallow the emitter to aim at so as to measure their vertical and/orhorizontal positions relative to the substrate surface.

At operation 906, light reflected from the substrate is collected at thereceiver of the substrate measuring device, and the receiver generatesdata or information related to the reflected light. The substratemeasuring device may be moved vertically, horizontally, and/ordiagonally relative to an X-Y plane of the substrate for facilitatingthe collecting of light reflected from the substrate. The substratemeasuring device may also be rotated at an angle to detect if thesubstrate is tilted. The substrate disposed on the stage may be moved ortranslated at certain directions relative to the substrate measuringdevice so as to scan the surface across the substrate.

At operation 908, after the light reflected from the substrate iscollected by the receiver and the data or information is generated, thedata points generated by the receiver are then analyzed to map out theprofile, height, and/or contour, or optionally, to determine thethickness of the photoresist layer on the substrate. Since the beams oflight with different wavelengths can reach to different depths of thephotoresist material as well as the material layer disposed on thesubstrate, variations in substrate height can be measured and obtainedso that a more accurate profile of the substrate surface is determined.Based on the determined substrate height map, a vertical position of anX-Y plane of the substrate relative to the focal plane may be determinedto better level the vertical position of the substrate. As a result, theposition of the X-Y plane of the substrate relative to the focal planeof the projection of the optical focusing module 104 is determined withhigher accuracy and image resolution.

At operation 910, after the substrate profile is mapped and a verticalposition relative to the focal plane is determined, the substrate isaligned for the lithography exposure process based on the mapping. Thestage and translation mechanism can be moved under the control of thecontroller to align the substrate based on the mapping.

At operation 912, the lithography exposure process is performed on thesubstrate. The light radiation from the radiation source 101 is passedthrough the photomask reticle 102 and focused on the focal plane by theassistance from the optical focusing module 104. Thus, the mask patternfrom the photomask reticle 102 is projected and exposed on thephotoresist material disposed on the substrate.

Embodiments described herein provide a substrate measuring device in alithography projection apparatus that includes an emitter that providesmultiple light sources having different wavelengths. The substratemeasuring device with multiple light sources can be used to provide abetter alignment of the substrate during a lithography exposure process.The multiple light sources may provide beams of light at differentwavelengths to be emitted to a substrate surface. The beams of lightwith different wavelengths may provide a wide spectrum of wavelengths,and the materials on the substrate can have different transmissivity andreflectivity based on the different wavelengths so that the variationsof the height of the structures formed on the surface of the substratecan be detected and mapped. In some examples, the emitter utilizesoptical fibers to guide the beams of light from the multiple lightsources to the desired locations on the substrate. The optical fibersmay include multiple zones to guide the beams of light with differentwavelengths. The multiple zones in the optical fiber may be fabricatedfrom different or the same materials. The emitter may include aplurality of optical fibers and some of the optical fibers may befabricated from the same or different materials to guide beams of lightwith different wavelengths.

In an embodiment, a lithography projection apparatus includes asubstrate measuring system disposed proximate to a substrate stage, thesubstrate measuring system further including an emitter includingmultiple light sources configured to provide multiple beams of light,each of at least some of the multiple beams of light having a differentwavelength, at least one optical fiber, wherein each of respectiveportions of the at least one optical fiber is configured to pass arespective one of the multiple beams of light, and a receiver positionedto collected light emitted from the emitter and reflected off of asubstrate disposed on the substrate stage.

In another embodiment, a method for semiconductor processing, the methodincludes providing beams of light from an emitter to a substrate,wherein the beams of light have multiple wavelengths, collectingreflected light of the beams of light at a receiver, the reflected lightbeing reflected off of the substrate, determining a variation of heightof the substrate based on the collected reflected light, and aligningthe substrate with an optical focusing module in response to thedetected variation of height of the substrate.

In yet another embodiment, a method for semiconductor processing, themethod includes emitting multiple beams of light from multiple lightsources from an emitter to a substrate, wherein the multiple beams oflight have different wavelengths, collecting reflected light of themultiple beams of light at a receiver, the reflected light beingreflected off of the substrate, mapping variations of height across thesubstrate based on the collected reflected light, determining a levelingposition of the substrate relative to a focus plane based on themapping, aligning the substrate at the leveling position, and performinga lithography exposure process on the substrate after aligning thesubstrate.

The foregoing outlines features of several embodiments so that thoseskilled in the art may better understand the aspects of the presentdisclosure. Those skilled in the art should appreciate that they mayreadily use the present disclosure as a basis for designing or modifyingother processes and structures for carrying out the same purposes and/orachieving the same advantages of the embodiments introduced herein.Those skilled in the art should also realize that such equivalentconstructions do not depart from the spirit and scope of the presentdisclosure, and that they may make various changes, substitutions, andalterations herein without departing from the spirit and scope of thepresent disclosure.

What is claimed is:
 1. A method for semiconductor processing, the methodcomprising: providing beams of light from an emitter to a substrate,wherein the beams of light have multiple wavelengths and are provided tothe substrate via at least one optical fiber including multiple zones,each of the multiple zones including strands of optical fibers, amaterial of the strands of optical fibers of a zone being different fromthe material of the strands of optical fibers of a different zone;collecting reflected light of the beams of light at a receiver, thereflected light being reflected off of the substrate; determining avariation of height of the substrate based on the collected reflectedlight; and aligning the substrate with an optical focusing module inresponse to the determined variation of height of the substrate.
 2. Themethod of claim 1, wherein the emitter comprises multiple light sourcesto provide the beams of light having the multiple wavelengths.
 3. Themethod of claim 1, wherein the multiple wavelengths are in a range from10 nm to 2000 nm.
 4. The method of claim 1, wherein the substratecomprises a photoresist layer disposed on a material layer.
 5. Themethod of claim 1, wherein providing the beams of light furthercomprises: directing the beams of light to an alignment mark on thesubstrate.
 6. The method of claim 1, wherein determining variation ofheight of the substrate further comprises: determining a verticalposition of the substrate relative to a focal plane defined by anoptical focusing module in a lithography projection apparatus.
 7. Themethod of claim 6, further comprising: performing a lithography exposureprocess in the lithography projection apparatus after aligning thesubstrate with the optical focusing module.
 8. The method of claim 6,wherein the emitter and the receiver are disposed in the lithographyprojection apparatus.
 9. The method of claim 1, wherein the beams oflight pass through at least one optical fiber disposed in the emitter.10. The method of claim 1, wherein the beams of light pass through atleast one polarizer.
 11. A method for semiconductor processing, themethod comprising: emitting multiple beams of light from multiple lightsources from an emitter to a substrate, wherein the multiple beams oflight have different wavelengths; shielding the substrate from a portionof the multiple beams of light utilizing a metal shield on the emitter;collecting reflected light of the multiple beams of light at a receiver,the reflected light being reflected off of the substrate; mappingvariations of height across the substrate based on the collectedreflected light; determining a leveling position of the substraterelative to a focus plane based on the mapping; aligning the substrateat the leveling position; and performing a lithography exposure processon the substrate after aligning the substrate.
 12. The method of claim11, wherein the shield is ring shaped and includes a center opening, aportion of the shield configured to block a portion of the multiplebeams of light and to allow a portion of the multiple beams of light topass through the center opening.
 13. The method of claim 11, wherein theshield serves as a frame covering an outer perimeter of the emitter andexposing a portion of the emitter through a center opening.
 14. Themethod of claim 11, further comprising passing at least one of themultiple beams of light through a polarizer.
 15. The method of claim 11,wherein the different wavelengths are in a range from 10 nm to 2000 nm.16. A method for semiconductor processing, the method comprising:providing light at multiple wavelengths from a broad spectrum lightsource of an emitter; filtering the light at multiple wavelengths toproduce multiple beams of light, each of at least some of the multiplebeams of light having a different wavelength; transmitting the multiplebeams of light from the emitter to a substrate, wherein the multiplebeams of light are provided to the substrate via at least one opticalfiber including multiple zones, each of the multiple zones includingstrands of optical fibers, a material of the strands of optical fibersof a zone being different from the material of the strands of opticalfibers of a different zone; collecting reflected light of the multiplebeams of light at a receiver, the reflected light being reflected off ofthe substrate; determining a variation of height of the substrate basedon the collected reflected light; and aligning the substrate with anoptical focusing module in response to the determined variation ofheight of the substrate.
 17. The method of claim 16, wherein themultiple beams of light include UV light or visible light.
 18. Themethod of claim 16, further comprising shielding the substrate from aportion of the multiple beams of light utilizing a shield on theemitter.
 19. The method of claim 18, wherein the shield is a metalshield.
 20. The method of claim 16 further comprising, polarizing atleast one of the multiple beams of light.